Tucked away in it all was this little bit at the end of the first article:

“Ice cores from Summit show that melting events of this type occur about once every 150 years on average. With the last one happening in 1889, this event is right on time,” says Lora Koenig, a Goddard glaciologist and a member of the research team analyzing the satellite data.

OK, which is it? A “record” or something repetitive? Maybe this post explains it a lot more clearly: